Explanation/Reference:
Section: Considerations for Expanding an Existing Network Explanation
Explanation:
You are installing a network device in a 7inch (18centimeter) space if you are installing a 4unit (U) device in a data center. Although most racks adhere to a standard width of 19 inches (about 48 centimeters), a certain number of U, or height, of space must be available within a rack to allow the installation of your equipment and to allow space between your equipment and other equipment that is contained within the rack. A U is equivalent to 1.75 inches (about 4.5 centimeters) of height. Therefore, if the device you want to install is a 2U device, the rack should have at least 3.5 inches (about 9 centimeters) of available space to accommodate the device and more to allow for space above and below the device. A 4U device will fit into a 7inch (18centimeter) rack space.
You are not installing a lock for rack security. However, rack security is likely to be a concern when installing a server in a third-party data center. Commercial data centers house devices for multiple customers within the same physical area. Although many data centers are physically secured against intruders who might steal or modify equipment, the data center's other customers have the same access to the physical area that you do. Therefore, you should install physical security mechanisms, such as a lock, at the rack level to ensure that your company's devices cannot be accessed by others.
You are not installing an environmental control. However, an environmental control such as airflow, which helps prevent devices from overheating, is likely to be a concern when installing a server in a third-party data center. You should choose a data center that provides environmental controls. For example, a hot and cold aisle layout is a data center design that attempts to control the airflow within the room in order to mitigate problems that can result from overheated servers? it essentially prevents hot air from mixing with cold air. A raised floor layout is a data center design that puts the heating, ventilation, and air conditioning (HVAC) ductwork below the floor tiles. The tiles, which are typically located in the aisles between the server racks in this type of environment, are perforated so that airflow can be directed and concentrated in the exact locations desired.
You are not installing cabling at the demarc, or demarcation point. The demarc is the termination point between a physical location and its service provider. In other words, it is the point where the responsibility of the physical location ends and the responsibility of the service provider begins. At a third-party data center, the demarc is the responsibility of the data center provider and its service provider, not the data center's customers.
Reference:
CCDA 200-310 Official Cert Guide, Chapter 4, Data Center Facility Aspects, pp. 136-138 Cisco: Cabinet and Rack Installation